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powerpc/64s: Convert slb_miss_common to use RFI_TO_USER/KERNEL

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commit c7305645eb upstream.

In the SLB miss handler we may be returning to user or kernel. We need
to add a check early on and save the result in the cr4 register, and
then we bifurcate the return path based on that.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Backport to 4.4 based on patch from Balbir]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Nicholas Piggin
2018-01-10 03:07:15 +11:00
committed by Greg Kroah-Hartman
parent 00e40620a5
commit 48cc95d4e4
1 changed files with 20 additions and 2 deletions
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22
arch/powerpc/kernel/exceptions-64s.S
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@@ -655,6 +655,8 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
andi. r10,r12,MSR_RI /* check for unrecoverable exception */
beq- 2f
andi. r10,r12,MSR_PR /* check for user mode (PR != 0) */
bne 1f
/* All done -- return from exception. */
@@ -671,7 +673,23 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
ld r11,PACA_EXSLB+EX_R11(r13)
ld r12,PACA_EXSLB+EX_R12(r13)
ld r13,PACA_EXSLB+EX_R13(r13)
rfid
RFI_TO_KERNEL
b . /* prevent speculative execution */
1:
.machine push
.machine "power4"
mtcrf 0x80,r9
mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */
.machine pop
RESTORE_PPR_PACA(PACA_EXSLB, r9)
ld r9,PACA_EXSLB+EX_R9(r13)
ld r10,PACA_EXSLB+EX_R10(r13)
ld r11,PACA_EXSLB+EX_R11(r13)
ld r12,PACA_EXSLB+EX_R12(r13)
ld r13,PACA_EXSLB+EX_R13(r13)
RFI_TO_USER
b . /* prevent speculative execution */
2: mfspr r11,SPRN_SRR0
@@ -679,7 +697,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)
mtspr SPRN_SRR1,r10
rfid
RFI_TO_KERNEL
b .
8: mfspr r11,SPRN_SRR0